Peanut butter is trans fat free

According to a study conducted by the US Agricultural Research
Service (ARS), peanut butters do not contain trans fats. Recurring
rumours that commercial...

According to a study conducted by the US Agricultural Research
Service (ARS), peanut butters do not contain trans fats. Recurring
rumours that commercial peanut butters contain trans fats are not
founded.
The rumours first started because small amounts (1-2 per cent of
total weight) of hydrogenated vegetable oils are added to
commercial peanut butters to prevent the peanut oil from separating
out. According to M. Sanders, lead researcher at the ARS's Market
Quality and Handling Research Unit, the hydrogenation process can
generate the formation of trans fatty acids in oils.
For the study, Sanders prepared 11 brands of peanut butter,
including major store brands and "natural"​ brands, for
analysis by a commercial laboratory. He also sent paste freshly
prepared from roasted peanuts for comparison. The laboratory found
no detectable trans fats in any of the samples, with a detection
limit of 0.01 per cent of the sample weight.
This means that a 32-gram serving of the studied peanut butters
contain zero to about 0.0032 gram of trans fats without being
detected. However, peanut butter has plenty of unsaturated fatty
acids. The most abundant is oleic acid, the monounsaturated fat
believed to be good for the cardiovascular system. In this
analysis, oleic acid levels ranged from 19 per cent of total weight
in one private-label brand to 27 per cent in one "natural"​
type.
Source: Agricultural Research Service​